JP5121734B2 - Power supply voltage forming apparatus and polar modulation transmitting apparatus - Google Patents

Description

  The present invention relates to a power supply voltage forming device that forms a power supply voltage to be supplied to a high-frequency power amplifier according to input data, and a polar modulation transmission device having such a power supply voltage forming device.

  Transmitter design generally has a trade-off between efficiency and linearity. However, recently, a technology that can achieve both high efficiency and linearity, such as a polar modulation transmission technology, has been proposed.

FIG. 1 shows a configuration example of a polar modulation transmission apparatus. The polar modulation transmission device 10 includes an amplitude / phase data forming unit 11, a phase modulator 12, a high frequency power amplifier (so-called power amplifier) 14, and a power supply voltage forming device 13 that forms a power supply voltage _VCC of the high frequency power amplifier 14. And have.

The amplitude / phase data forming unit 11 forms a baseband amplitude signal S1 and a baseband phase signal S2 from the input transmission signal. Here, the baseband amplitude signal S1 is a signal represented by √ (I ² + Q ² ) when the in-phase component of the transmission signal is represented by I and the quadrature component is represented by Q. The baseband phase signal S2 is a phase component of the transmission signal (for example, an angle formed by a modulation symbol and the I axis).

  The phase modulator 12 modulates the carrier frequency signal with the baseband phase signal S <b> 2 to form a high frequency phase modulation signal S <b> 3 and outputs it to the signal input terminal of the high frequency power amplifier 14.

The power supply voltage forming device 13 forms the power supply voltage _VCC supplied to the power supply terminal of the high frequency power amplifier 14 based on the baseband amplitude signal S1.

Thus, from the high-frequency power amplifier 14, the signal multiplied with the power supply voltage value V _CC and the high frequency phase modulation signal S3 is amplified by the gain amount of the high-frequency power amplifier 14, the transmission output signal is output as a result . The transmission output signal is transmitted from an antenna (not shown).

  By using such a polar modulation transmission technique, the high frequency phase modulation signal S3 input to the high frequency power amplifier 14 can be a constant envelope signal having no fluctuation component in the amplitude direction. As a result, a highly efficient nonlinear amplifier can be used.

By the way, in such a polar modulation transmission apparatus 10, the power supply voltage value V _CC formed based on the baseband amplitude signal S1 and the output voltage of the high frequency power amplifier 14 (generally, the transmission output signal in the figure is 50Ω). It is required to have a proportional relationship with the voltage obtained by converting the voltage applied to

  Here, as an element used for the high frequency power amplifier 14, an HBT (Hetero-junction Bipolar Transistor) device that can obtain a higher gain than an FET (Field effect transistor) device and can be easily downsized is used. There are many cases. However, the HBT device has a specific parameter called an offset voltage between the power supply voltage value and the output voltage.

FIG. 2 shows the relationship between the power supply voltage value _VCC and the output voltage when the high-frequency power amplifier 14 is configured using an HBT device. The solid line in the figure shows the relationship between the power supply voltage value _VCC and the output voltage when the HBT device is used, and the power supply voltage value _VCC and the output voltage change linearly. Since it does not pass through the origin, it can be seen that there is no proportional relationship. The offset voltage is a power supply voltage value when the output rises. In FIG. 2, the relationship between the power supply voltage value _VCC and the output voltage is approximated by a straight line, and the intersection of the straight line and the x axis is defined as the offset voltage. ing.

Conventionally, in the polar modulation transmission apparatus 10, in order to control the output power of the high-frequency power amplifier 14 (that is, the power of the transmission output signal), the power supply voltage forming apparatus 13 adjusts the level of the baseband amplitude signal S1. 2 has been proposed in which the offset voltage shown in FIG. 2 is added to the level-adjusted baseband amplitude signal so that the power supply voltage value _VCC and the output voltage are in a proportional relationship (for example, a patent). Reference 1). By doing in this way, generation | occurrence | production of the distortion resulting from offset can be avoided.

This configuration will be briefly described with reference to FIG. The power supply voltage generator 13 in FIG. 3 inputs the baseband amplitude signal S1 to the level adjuster 21. The level adjustment unit 21 adjusts the level of the baseband amplitude signal S1 according to, for example, a scaling coefficient from a transmission power control unit (not shown), and sends the baseband amplitude signal after the level adjustment to the offset addition unit 23. . Offset adding unit 23, the baseband amplitude signal after the level adjustment, by adding an offset voltage generated by the offset voltage generating unit 22 to form a power supply voltage V _CC of high frequency power amplifier 14, which high-frequency power The power is supplied to the power supply terminal of the amplifier 14.
US Pat. No. 6,998,919

  However, as shown in FIG. 3, since the method of adding the offset voltage after controlling the level of the baseband amplitude signal S1 is usually analog signal processing, when viewed from the path for processing the baseband amplitude signal S1. The offset voltage generator 22 becomes a load. As a result, there is a problem that the transmission output signal output from the high frequency power amplifier 14 is likely to be distorted particularly when the signal level after level adjustment is high, that is, at high output.

  An object of the present invention is to provide a power supply voltage forming device and a polar modulation transmission device capable of correcting an offset voltage of a high frequency power amplifier without degrading the distortion characteristics of the high frequency power amplifier.

A power supply voltage forming apparatus according to the present invention is a power supply voltage forming apparatus that forms a power supply voltage to be supplied to a high-frequency power amplifier based on input data, the first digital-analog converter converting the input data into digital-analog, A level adjusting unit for adjusting the level of the input data after analog conversion based on an output level control value for controlling the output level of the high-frequency power amplifier; and a second digital / analog conversion for converting the offset data into digital analog An analog offset addition unit that analog-adds the analog-converted offset data to the level-adjusted signal, a digital offset addition unit that digitally adds the offset data to the input data before analog conversion, Select addition by analog offset adder First an addition selection mode, and a second addition selecting mode for selecting the addition by the digital offset adding section, when the output level control value indicates a time of high output said second summing selection mode And a selection unit that selects the first addition selection mode when the output level control value indicates a low output .

  According to the present invention, since the offset value is switched between digital addition and analog addition based on the output level control value, the mode is switched from the analog addition mode to the digital addition mode at the time of high output. Will be able to. As a result, the offset voltage of the high frequency power amplifier can be corrected without degrading the distortion characteristics of the high frequency power amplifier.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Embodiment 1)
FIG. 4 shows a basic configuration of the power supply voltage forming apparatus according to the embodiment of the present invention. The power supply voltage forming apparatus 100 forms a power supply voltage _VCC supplied to the power supply terminal of the high frequency power amplifier 200. The high frequency power amplifier 200 is configured by an HBT system device.

  The power supply voltage forming apparatus 100 inputs input data to the digital adder 101. This input data corresponds to a baseband amplitude signal when the power supply voltage forming apparatus 100 is used in a polar modulation transmission apparatus.

  The digital adder 101 adds offset data to input data. The offset data is data corresponding to the offset voltage shown in FIG. 2, and is stored in advance in a memory (not shown). The output of the digital adder 101 is sent to the level adjustment unit 103 via the digital / analog converter (D / A) 102.

  The level adjustment unit 103 adjusts the output signal level of the digital-analog converter 102 according to the output level control value for controlling the output level of the high-frequency power amplifier 200. Here, the output level control value is a signal formed by a transmission power control unit (not shown). The signal whose level is adjusted by the level adjusting unit 103 is sent to the analog adder 104.

  In addition to the signal from the level adjustment unit 103, offset data is input to the analog adder 104 via a digital / analog converter (D / A) 105. Thus, the analog adder 104 analog-adds the analog-converted offset voltage to the analog signal output from the level adjustment unit 103.

  In addition to such a configuration, the power supply voltage forming apparatus 100 includes a selection unit 106 that selects whether offset data is added by the digital adder 101 or offset voltage is added by the analog adder 104. The selection unit 106 performs the above selection based on the output level control value.

  Specifically, when the output level control value is greater than or equal to a predetermined value (that is, during high output), the selection unit 106 controls the switch 107 to be turned on to cause the digital adder 101 to add offset data, By performing the OFF control of the switch 108, the addition by the analog adder 104 is not performed. The case where the output level control value is equal to or greater than the predetermined value here refers to the case where the output level of the high-frequency power amplifier 200 is large and distortion is likely to occur in the transmission output signal when the analog adder 104 adds the offset voltage in analog.

  On the other hand, when the output level control value is less than the predetermined value (that is, at the time of low output), the selection unit 106 does not perform the addition of the digital adder 101 by controlling the switch 107 to be OFF, The offset voltage is added by the analog adder 104 by turning on the switch 108. The case where the output level control value is less than the predetermined value here is a case where the output level of the high-frequency power amplifier 200 is small, and even if the analog adder 104 adds the offset voltage in an analog manner, the influence on the transmission output signal is small. Sure.

  As described above, when the output is high (when the output level of the level adjustment unit 103 is high, in other words, when the output level of the high-frequency power amplifier 200 is high), the offset data is digitally added, and otherwise the analog addition is performed. By doing so, the offset of the high-frequency power amplifier 200 can be corrected without degrading the distortion characteristics of the high-frequency power amplifier 200.

Here, at the time of high output, when viewed from the signal path from the level adjustment unit 103 to the high-frequency power amplifier 200, the offset voltage generation circuit (in the case of FIG. 4, the digital-analog converter 105) becomes a load. The power supply voltage _VCC supplied to the amplifier 200 is distorted, and as a result, the distortion characteristics of the output signal of the high frequency power amplifier 200 are also deteriorated.

  However, in the power supply voltage forming apparatus 100 of the present embodiment, at the time of high output, the path between the analog adder 104 and the digital-analog converter 105 is blocked by the switch 108, so that no distortion occurs. Further, since the offset is corrected by digital addition by the digital adder 101, distortion due to the offset does not occur.

  On the other hand, when the output is low, if the offset data is digitally added by the digital adder 101 before the conversion by the digital-analog converter 102, the offset data in anticipation of the attenuation amount of the level adjusting unit 103 must be digitally added. For example, when the signal level is attenuated by 20 dB by the level adjusting unit 103, it is necessary to add offset data corresponding to 10 times the voltage by the digital adder 101, which is not practical.

  However, in the power supply voltage forming apparatus 100 of the present embodiment, at the time of low output, the offset voltage is added by the analog adder 104 without adding the offset data by the digital adder 101. The offset can be corrected without digitally adding the offset data.

As described above, according to the present embodiment, the first digital-analog converter 102 that performs digital-to-analog conversion of input data, the level of the analog-converted input data, and the output level of the high-frequency power amplifier 200 are controlled. A level adjusting unit 103 that adjusts based on the output level control value for performing the conversion, a second digital-to-analog converter 105 that converts the offset data from digital to analog, and the analog-converted offset data into the level-adjusted signal. Analog adder 104 that performs analog addition, digital adder 101 that digitally adds offset data to the input data before analog conversion, and addition by analog adder 104 or digital addition based on the output level control value Select whether to perform addition by the device 101 By providing the selection unit 106, the offset of the high-frequency power amplifier 200 is corrected while avoiding the occurrence of distortion caused by analog addition when the power supply voltage corresponding to the input data and the output level control value is formed. A power supply voltage _VCC that can be _generated can be formed.

  In addition, in the case of low output with low distortion due to analog addition (when the output level control value is small), the offset data with a large number of digits is digitally added by analog addition without digital addition of offset data. Since it is not necessary, the configuration of the digital adder 101 can be simplified.

(Embodiment 2)
FIG. 5 shows the configuration of the power supply voltage forming apparatus according to the second embodiment. The power supply voltage forming apparatus 300 according to the present embodiment basically performs the same operation as that of the power supply voltage forming apparatus 100, but some devices are added to the configuration.

  The digital adder 301 receives input data and selectively receives output data of the offset scaling unit 307 or all “0” data from the selection unit 306, and inputs or all data after offset scaling to the input data. Add “0” data. The output of the digital adder 301 is sent to a variable attenuator (ATT) 303 via a digital / analog converter (D / A) 302.

  The variable attenuator 303 corresponds to the level adjustment unit 103 in FIG. 4 and attenuates the output signal of the digital-analog converter 302 according to the scaling coefficient. Note that the scaling coefficient corresponds to the output level control value in FIG. 4 and is, for example, a signal formed by the transmission power control unit. The signal whose level is adjusted by the variable attenuator 303 is sent to the analog adder 304.

  In addition to the signal from the variable attenuator 303, the analog adder 304 selectively receives an offset voltage or a voltage value of 0 [V] that is analog-converted by the digital-analog converter (D / A) 305 from the selection unit 308. Is input. Accordingly, the analog adder 304 adds an offset voltage or 0 [V] to the signal from the variable attenuator 303 in an analog manner.

  Here, the offset scaling unit 307 inputs the offset data and the scaling coefficient, and based on the output level control value, the offset data is converted into the level adjustment amount by the level adjustment unit (variable attenuator 303 in this embodiment). It is designed to be reciprocal times. In other words, the offset scaling unit 307 outputs a value obtained by dividing the offset data by the attenuation amount of the variable attenuator 303 as digital data after offset scaling. As a result, when the offset voltage after digital addition is attenuated by the variable attenuator 303, the offset voltage value after attenuation can be made a desired offset voltage corresponding to the offset data.

The selection unit 306 selects the output of the offset scaling unit 307 and supplies it to the digital adder 301 when the scaling coefficient is equal to or greater than a predetermined value (that is, at high output). The selection unit 308 selects the ground voltage (GND) and supplies it to the analog adder 304 when the scaling coefficient is equal to or greater than a predetermined value. Thereby, at the time of high output, the offset voltage is substantially digitally added by the digital adder 301, and analog addition by the analog adder 304 is not performed. As a result, at high output, the offset voltage can be corrected by digital addition without causing distortion due to analog addition.

  On the other hand, the selection unit 306 supplies all “0” digital data to the digital adder 301 when the scaling coefficient is less than a predetermined value (that is, at the time of low output). In addition, when the scaling coefficient is less than the predetermined value, the selection unit 308 selects the offset voltage output from the digital / analog converter 305 and supplies the selected offset voltage to the analog adder 304. Thereby, at the time of low output, the offset voltage is substantially analog-added by the analog adder 304, and the digital addition by the digital adder 301 is not performed. As a result, the offset voltage can be corrected by analog addition without digitally adding offset data having a large number of digits.

  The above-described switching between digital addition and analog addition will be specifically described with reference to FIG. FIG. 6 shows an example when the input data is a baseband amplitude signal (amplitude signal in the figure) in polar modulation. 6 shows that the maximum dynamic range of the amplitude signal is 1 [Vpp], the maximum adjustment range of the offset voltage is 0.2 [V], and the maximum dynamic range of the digital-analog converter 302 is 0 to 1.4 [V]. An example of the case is shown. In FIG. 6, the amplitude signal range is a range excluding the offset voltage. In FIG. 6, all are converted into analog values.

  FIG. 6 shows how the dynamic range of each signal before and after scaling changes according to the scaling amount of the variable attenuator when digitally adding an offset voltage of 0.2 [V] to the amplitude signal (input data). It is shown.

  The limit in digitally adding offset data is that the total signal range after digital addition does not exceed the maximum dynamic range of the digital-analog converter 302. In this example, if the scaling amount (set value of ATT 303) is up to about −6 [dB], the total signal range after digital addition does not exceed the maximum dynamic range of 1.4 [V] of the digital-analog converter 302. Therefore, digital addition is performed when the scaling amount is −6 [dB] or more, and analog addition is performed when the scaling amount is less than that.

  That is, according to the present embodiment, the same effect as in the first embodiment can be obtained with the same configuration as in the first embodiment.

  In addition, a threshold value is determined for the scaling coefficient (corresponding to the output level control value in the first embodiment), and digital data is added when the offset data is digitally added or the offset voltage is analogly added according to the determination result. By performing threshold setting in consideration of the dynamic range of the analog converter 302, signal degradation in the digital-analog converter 302 can be suppressed.

  Further, by providing an offset scaling unit 307 that scales the offset data so as to correspond to the data obtained by multiplying the offset data by the inverse of the level adjustment amount by the variable attenuator 303 based on the scaling coefficient, the data after passing through the variable attenuator 303 The offset voltage value can be a desired offset voltage corresponding to the offset data.

(Embodiment 3)
FIG. 7 in which parts corresponding to those in FIG. 5 are assigned the same reference numerals shows the configuration of the power supply voltage forming apparatus according to the third embodiment.

  The power supply voltage forming apparatus 400 inputs offset data to the selection units 401 and 402 in addition to the scaling coefficient. The selection units 401 and 402 are configured to switch between digital addition of the offset data and analog addition of the offset voltage based on both the scaling coefficient and the offset data.

  Specifically, in the case of the first offset data, the first scaling coefficient is set as the switching threshold, and in the case of the second offset data different from the first offset data, the first scaling coefficient and A different second scaling factor is set as the switching threshold.

  That is, in the second embodiment, the example in which the scaling amount (−6 [dB]) corresponding to the maximum offset data (0.2 [V]) is used as the switching threshold is described with reference to FIG. In the embodiment, the scaling amount used as the threshold value is also changed according to the offset data.

  Thereby, compared with the case where digital addition and analog addition are simply switched according to the maximum value of the offset data, the area for digital addition can be expanded without difficulty according to the magnitude of the offset.

  8 shows how digital addition and analog addition are switched when the value of the offset data (“offset voltage after passing ATT” in the figure) is 0.1 [V]. The operation | movement on the conditions similar to FIG. 6 is shown.

  As shown in FIG. 8, when the offset voltage (value indicated by the offset data) is 0.1 [V] and the scaling amount (ATT set value) is up to about −12 [dB], the total signal after the digital addition is performed. The range does not exceed the maximum dynamic range 1.4 [V] of the digital-analog converter 302. Therefore, power supply voltage generating apparatus 400 of the present embodiment performs digital addition when the scaling amount is −12 [dB] or more, and performs analog addition when the scaling amount is less than that.

  When the offset voltage to be set is 0.2 [V], the power supply voltage forming apparatus 400 performs digital addition when the scaling amount is −6 [dB] or more as shown in FIG. If the amount is less than that, an analog addition is performed.

  As described above, according to the present embodiment, the scaling amount is threshold-determined, and whether the offset voltage is added by the analog adder 304 or the offset data is added by the digital adder 301 is switched based on the determination result. Since the threshold value is changed according to the offset data, in addition to the effects of the first and second embodiments, the area of digital addition can be expanded to the maximum.

(Embodiment 4)
FIG. 9 in which the same reference numerals are assigned to the parts corresponding to those in FIG. 5 shows the configuration of the power supply voltage forming apparatus according to the fourth embodiment.

  The power supply voltage generation apparatus 300 according to the second embodiment described with reference to FIG. 5 selects the first addition selection mode in which the selection units 306 and 308 select addition by the analog adder 304 and the addition by the digital adder 301. The second addition selection mode is selected, and either the first addition selection mode or the second addition selection mode is selected based on the scaling coefficient (that is, the output level control value).

  In power supply voltage generating apparatus 600 of the present embodiment, selection units 601 and 602 select addition by both analog adder 304 and digital adder 301 in addition to the first and second addition selection modes. A third addition selection mode is further provided, and one of the first to third addition selection modes is selected based on a scaling coefficient (that is, an output level control value).

  In addition, the power supply voltage generation apparatus 600 according to the present embodiment includes an offset data conversion unit 603. Based on the scaling coefficient, the offset data conversion unit 603 converts the offset data into analog addition offset data input to the digital / analog converter (D / A) 305 and digital addition offset input to the offset scaling unit 307. Convert to data.

  The selection unit 601 selects the output of the offset scaling unit 307 and supplies it to the digital adder 301 when the scaling coefficient is greater than or equal to the first predetermined value (that is, at high output). The selection unit 602 selects the ground voltage (GND) and supplies the ground voltage (GND) to the analog adder 304 when the scaling coefficient is equal to or greater than the first predetermined value. Thereby, at the time of high output, the offset voltage is substantially digitally added by the digital adder 301, and analog addition by the analog adder 304 is not performed. As a result, at high output, the offset voltage can be corrected by digital addition without causing distortion due to analog addition.

  In addition, the selection unit 601 selects the output of the offset scaling unit 307 when the scaling coefficient is less than the first predetermined value and greater than or equal to the second predetermined value (that is, during medium output), and the digital adder 301 Supply. The selection unit 602 selects the offset voltage output from the digital-analog converter 305 and supplies the offset voltage to the analog adder 304 when the scaling coefficient is less than the first predetermined value and greater than or equal to the second predetermined value. Thereby, at the time of medium output, addition is performed by both the digital adder 301 and the analog adder 304. That is, the offset voltage is substantially digitally added by the digital adder 301 and further analog-added by the analog adder 304.

  Further, the selection unit 601 supplies all “0” digital data to the digital adder 301 when the scaling coefficient is less than the second predetermined value (that is, at the time of low output). In addition, when the scaling coefficient is less than the second predetermined value, the selection unit 602 selects the offset voltage output from the digital / analog converter 305 and supplies the selected offset voltage to the analog adder 304. Thereby, at the time of low output, the offset voltage is substantially analog-added by the analog adder 304, and the digital addition by the digital adder 301 is not performed. As a result, the offset voltage can be corrected by analog addition without digitally adding offset data having a large number of digits.

  The offset data conversion unit 603 supplies the offset data as it is to the offset scaling unit 307 when the scaling coefficient is equal to or greater than the first predetermined value (that is, at the time of high output). Similarly, the offset data conversion unit 603 outputs the offset data as it is to the digital-analog converter (D / A) 305 when the scaling coefficient is less than the second predetermined value (that is, at the time of low output).

  On the other hand, the offset data conversion unit 603 converts the offset data into analog addition offset data when the scaling coefficient is less than the first predetermined value and greater than or equal to the second predetermined value (that is, during medium output). Then, the data is output to the digital / analog converter (D / A) 305, converted into offset data for digital addition, and output to the offset scaling unit 307.

  The above-described switching between digital addition and analog addition will be specifically described with reference to FIG. FIG. 10 shows an example when the input data is a baseband amplitude signal (amplitude signal in the figure) in polar modulation. FIG. 10 shows that the maximum dynamic range of the amplitude signal is 1 [Vpp], the maximum adjustment range of the offset voltage is 0.2 [V], and the maximum dynamic range of the digital-analog converter 302 is 0 to 1.4 [V]. An example of the case is shown. In FIG. 10, the amplitude signal range is a range excluding the offset voltage. In FIG. 10, all are converted into analog values.

  FIG. 10 shows a case where an offset voltage of 0.2 [V] is digitally added to the amplitude signal (input data) in a range where the scaling amount (set value of ATT 303) is larger than −6 [dB]. In FIG. 10, when the scaling amount (set value of ATT 303) is in the range of −6 [dB] to −12 [dB], the offset voltage of 0.1 [V] is digitally added and 0.1 [V] is added. A case is shown in which the offset voltage is added in an analog manner. FIG. 10 shows a case where an offset voltage of 0.2 [V] is added in an analog manner when the scaling amount (set value of ATT 303) is smaller than −12 [dB]. Furthermore, in FIG. 10, the dynamic range of each signal before and after scaling is the scaling of ATT 303 in each case where only digital addition is performed, both digital addition and analog addition are performed, and only analog addition is performed. It shows how it varies depending on the amount.

  The limit when digitally adding offset data is that the total signal range after digital addition does not exceed the maximum dynamic range of the digital-analog converter 302. In the case of the example in FIG. 10, the total signal range after digital addition does not exceed the maximum dynamic range of 1.4 [V] of the digital-analog converter 302 in the entire scaling amount (set value of ATT 303).

  Further, in the second embodiment, the offset voltage to be analog-added changes from 0 [V] to 0.2 [V] with a scaling amount of −6 [dB] as a boundary. Thus, it can be seen that the offset voltage to be analog-added changes from [0] V to 0.1 [V], and the change in the offset voltage is halved compared to the second embodiment.

  It is clear that the more rapid the voltage change, the longer the response time until convergence. In this embodiment, the influence of such a transient response can be reduced.

  In this embodiment, the threshold of the scaling amount is set to two locations of −6 [dB] and −12 [dB] in order to simplify the description. However, the digital addition amount and the analog addition amount of the offset voltage are used. It is possible to further increase the number of thresholds by finely changing the distribution. That is, FIG. 10 shows the case where both the digital addition offset data and the analog addition offset data are set to 0.1 [V], but the value of the digital addition offset data and the analog addition offset data are shown. It is not necessary to make the value of the offset data equal, and the distribution may be changed. In short, the sum of the digital addition offset data and the analog addition offset data may be equal to the offset data input to the offset data conversion unit 603.

  As described above, according to the present embodiment, in addition to the first addition selection mode in which the addition by the analog adder 304 is selected and the second addition selection mode in which the addition by the digital adder 301 is selected, the analog addition mode is selected. By providing a third addition selection mode that selects addition by both the adder 304 and the digital adder 301, the influence of the transient response that occurs due to the change in the voltage to be added in analog when the mode is switched is mitigated. can do.

  Needless to say, by adding the contents of the third embodiment to the present embodiment, the area of digital addition can be maximized.

(Other embodiments)
FIG. 11 shows a configuration of a polar modulation transmission apparatus on which power supply voltage forming apparatus 100 (300, 400, 600) according to Embodiments 1 to 4 described above is mounted. Polar modulation transmission apparatus 500 includes amplitude / phase data forming section 501, phase modulator 502, transmission power control section 503, high-frequency power amplifier (so-called power amplifier) 200, and the power source described in the first to fourth embodiments. Voltage forming apparatus 100 (300, 400, 600).

  The amplitude / phase data forming unit 501 forms a baseband amplitude signal and a baseband phase signal from the input transmission signal. The phase modulator 502 modulates the carrier frequency signal with the baseband phase signal to form a high frequency phase modulation signal and outputs it to the signal input terminal of the high frequency power amplifier 200.

Supply voltage forming apparatus 100 (300,400,600) based on the baseband amplitude signal to form a power supply voltage _{V CC} supplied to the power supply terminal of the RF power amplifier 200. Here, the baseband amplitude signal corresponds to input data to the digital adder 101 (301) in FIG. 4, FIG. 5, FIG. 7 and FIG. Further, the power supply voltage forming apparatus 100 (300, 400, 600) has a transmission power control from the transmission power control unit 503 corresponding to the output level control value of FIG. 4 and the scaling coefficients of FIGS. A signal is input.

  In polar modulation transmission apparatus 500 equipped with power supply voltage generation apparatus 100 (300, 400, 600) of Embodiments 1 to 4, the offset of high-frequency power amplifier 200 is reduced without degrading the distortion characteristics of high-frequency power amplifier 200. Since it can correct | amend, a high quality transmission output signal can be obtained.

  In addition, this invention is not limited to embodiment mentioned above, It can change and implement in the range which does not deviate from the main point.

  The disclosure of the specification, drawings and abstract contained in the Japanese application of Japanese Patent Application No. 2007-022000 filed on Jan. 31, 2007 is incorporated herein by reference.

  The present invention can correct an offset without degrading distortion characteristics even when a high-frequency power amplifier is configured using an HBT-based device. For example, various wireless devices using a high-frequency power amplifier such as a mobile phone Widely applicable to.

Block diagram showing the configuration of a conventional polar modulation transmitter A characteristic diagram showing the relationship between the power supply voltage value _VCC and the output voltage when an HBT device is used The block diagram which shows the structural example of the conventional power supply voltage formation apparatus The block diagram which shows the structure of the power supply voltage formation apparatus which concerns on Embodiment 1 of this invention. FIG. 3 is a block diagram showing a configuration of a power supply voltage forming apparatus according to a second embodiment. The figure which uses for description of addition operation switching of the power supply voltage formation apparatus of Embodiment 2 FIG. 4 is a block diagram showing a configuration of a power supply voltage forming apparatus according to a third embodiment. The figure which uses for description of addition operation switching of the power supply voltage formation apparatus of Embodiment 3 Block diagram showing a configuration of a power supply voltage forming apparatus according to a fourth embodiment The figure which uses for description of addition operation switching of the power supply voltage formation apparatus of Embodiment 4 The block diagram which shows the structure of the polar modulation transmission apparatus carrying the power supply voltage formation apparatus of this invention

Claims (7)

A power supply voltage forming device for forming a power supply voltage to be supplied to a high frequency power amplifier based on input data,
A first digital-to-analog converter for digital-to-analog conversion of the input data;
A level adjusting unit that adjusts the level of the input data that has been analog-converted based on an output level control value for controlling the output level of the high-frequency power amplifier;
A second digital-to-analog converter for converting the offset data from digital to analog;
An analog offset addition unit that analog-adds the analog-converted offset data to the level-adjusted signal;
A digital offset adder for digitally adding the offset data to the input data before analog conversion;
A first addition selection mode for selecting addition by the analog offset addition unit; and a second addition selection mode for selecting addition by the digital offset addition unit, wherein the output level control value indicates a high output level. A selection unit that selects the second addition selection mode in the case, and the first addition selection mode when the output level control value indicates a low output ;
A power supply voltage forming apparatus comprising: The selection unit further includes a third addition selection mode for selecting addition by both the analog offset addition unit and the digital offset addition unit, and when the output level control value indicates a medium output time, The power supply voltage generation device according to claim 1, wherein the third addition selection mode is selected. The power supply voltage forming apparatus according to claim 2, further comprising an offset data conversion unit that converts the offset data into digital addition offset data and analog addition offset data based on the output level control value. The power supply according to claim 1, further comprising: an offset scaling unit that multiplies the offset data input to the digital offset adder by a reciprocal of a level adjustment amount by the level adjustment unit based on the output level control value. Voltage forming device. The selection unit determines a threshold value for the output level control value, selects either the first or the second addition selection mode based on the determination result, and changes the threshold value according to offset data. The power supply voltage forming apparatus according to claim 1. The selection unit determines a threshold value for the output level control value, selects one of the first to third addition selection modes based on the determination result, and changes the threshold value according to offset data. The power supply voltage forming apparatus according to claim 2. The power supply voltage forming device according to claim 1, wherein a baseband amplitude signal is input as the input data;
A high-frequency power amplifier that inputs a power supply voltage formed by the power supply voltage formation to a power supply terminal and inputs a high-frequency phase modulation signal to a signal input terminal;
A polar modulation transmission apparatus comprising:

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